Selective signaling system



June 21, 1938. A. s. BENJAMIN 2,121,182

. SELECTIVE SIGNALING SYSTEM Filed Feb. 7, 1934 Ff/a 2 /2 W paLAQ MAQG/NAL ATTOR Y Patented June 21, 1938 UNITED STATES PATENT OFFICE 2,121,182 I SELECTIVE SIGNALING SYSTEM AbrahamS. Benjamin, Chicago,I-ll., assignor to Teletype Corporation, Chicago, Ill.,va corporation of Delaware Application February 7, 1934, Serial Noffi o v *1 Claims. 01. rim-s52) This invention pertains to signaling systems andmore particularly to composite fire alarm and printing telegraph systems arranged to permit transmission to a plurality of stations simultaneously. v

The principal object of the invention is the provision of a signaling system'including a central or control station and a'plurality of distant stations arranged so that the control station may communicate telegraphically or through the operation of audible signaling apparatus with all of thestations or with any group of the stations.

Another object is to provide for dividing the distant stations into groups so that one or more groups of stations may beselected to receive a message and other groups excluded from such message. i

The above and other objects of the invention are attained by connecting ,a plurality of stations together in groups by a line wire and then extending that line wire to a central oflice and proceeding thus until all stations are connected in several such groups. line wire has a switch by which one group or more or all groups may be connected to a transmitter which will transmit upon the selected line wires the signals suitable for the messagetobe transmitted. Thus a selectivity in type of signals is employed to enable the operator at the central office to sen-d electrical signals of different kinds to operate at the stations electrical receiving devices of difi'erent classes, the equipment at the stations being such that each station is equipped with a plurality of different types of signal receiving devices and the devices are so associated that any signaldevice may be operated independently of all other signal devices at that station.

The apparatus at each station comprises an audible signal deviceor a plurality of such devices and also a printing telegraph receiving device. These several receiving devices are associated with the line wire by means responsive selectively to signals in the line such that only one receiving device will respond to anysignals sent from the control oflice.

At the central control ofiice a signal transmitting device for each type of signal to be transmitted is provided, and switches are arranged to permit any transmitting device to be connected to any line or to any group of lines at one time.

A better understanding of the invention may be had from the following description, taken in conjunction with the accompanying drawing, wherein Fig. 1 shows line circuits with stations indi- At the central office, each i cated and with details of central office control apparatus, and .I' by r t Fig. 2 shows details of a station.

Printing telegraph{transmitting equipment is provided which'maybroadcastby suitable cur- 5'5 rents to the stations in groups, andvmanual impulsing keys are provided which will supply to the stations signal impulses of .certaincurrent strength for operating either of two signal bells according tothe polarity of thelapplied current. Switches are arranged for transferringjsignal lines fromthe printingservice to the bell operating service and vice versa.

Acontrol circuit for printing telegraph signals comprises telegraphf transmitter l, telegraph 15 printer 2, and transmitting relays 3, 4, and 5, whose cont aQtstand armatures are connected. through contacts of keys 6, "I, and 8 to lines 9, ill, and Vljl which have each a plurality of sta- I tions l2. Any key may be, operated to transfer its associated line from the printing telegraph control circuittojthe bell control key l3 and any orall keyst, 1, 8, maybe operated atone time.

Each station 12 has circuits and apparatus as M shown in Fig. '2 in'which three line relays are connected in thej'circuit .ofr the signaling line. Relay lfl responds to polar signals and has two contacts 5 and lfi and a tongue I! whichis I101? mally held .out of contactwith either contact by a centering springjl8. Relay l4 ismarginal and will opera'te only when supplied with a current of 50 milliamperes or more and responds selectivelyto polar currents either to close tongue I!v to contact l5 to' operate bell l9 by current from battery 20, or to close tongue H to contact I6 to operate bell Z Iby current from battery 20.

Relay 22 ispola-r and is sensitive to currents of value 'less than 50 milliamperes, and by its contact it controls the operationof a telegraphic receiving printer23 by currentfrom battery 24.

,Relay 25 is marginal and responds whenever relay l4 responds to current in the signaling line. The function of relay 25 is llOuDIGVGllt the operation of the receiving printer 23 upon signals which operate relay {,4 and which also operate relay 22. This function is effected by providing the armatureof relay 25 with a contact to operate a slowto-release relay 26 which by a cascade circuit operates a slow-to-release relay 21 which short circuits contacts oflrelay 22 and closes the circuit of receiving printer 23 so that it will be unresponsive to control by relay 22.

Station l2 therefore requires a strong positive curtentjtofoperate relay [4 to operate bell IS, a strong hegativecurrent to operate relay M to operate bell 2|, and at other times it requires weaker currents, both positive and negative, in properly timed signals to operate relay 22 to control the receiving printer 23. These several currents may be supplied by controlling mechanism at the central ofiice, Fig. 1.

Keys 6, 1, and 8 are shown set for connection of lines 9, I0, and II to contacts of relays 3, 4, and 5, and the system thus is shown in condition for transmission of printing telegraph signals. Operation of transmitter I causes code signals upon relays 3, 4, and 5, and each such operation causes a reversal of current in lines 9, III, and II. With relay 3 energized as shown, current from battery 30 flows through'wire 3|, resistor 32, front contact and armature 33, "wire 34,'in'ner contact and switch spring 35, line wire 9 and stations I2, switch spring 36 and inner contact, wire 31, armature 38 and frontcontact, resistor 39, and wire 40. When relay 3 is deenergized for a spacing signal, current flows from positive pole of battery 30, through wire 3|, resistor 32, back contact and armature 38, wire 31, inner contact and switch spring 36, line wire 9 and stations I2, switch spring 35 and contact, wire 34, armature 33 and back contact, resistor 39, and wire 40. The polar direction of. the current through linewire 9 is reversed by operation of relay 3 and transmitter I and relay 3 thus controls polar relays 22 at all stations I2 in line 9, signals being repeated in a local circuit containing battery 24 and receiving printer 23 and thus recording upon receiving printer 23 all messages generated by transmitter I at the central oflice.

,Key when operated to its alternative position, connects its springs 35 and 36 to outer contacts and provides a circuit for operation of manual impulsing key I3. When key I3 is operated downwardly, it engages its lower contact 4| and closes a circuit for current from negative battery 42 through contact 4|, key I3, wire 43, resistor 44, outer contact and switch spring 35, line 9 and stations I2, operated switch spring 36 and outer contact, resistor 45, and wire 46 to battery 42. Alternatively, when key I3 is operated upwardly it engages its upper contact 41 and provides a circuit for current from positive battery 48 through contact 41, key I3, wire 43, resistor 44, outer contact and switch spring 35, line 9 and stations I2, operated switch spring 36 and outer contact, resistor 45, and wire 46 to battery 48.

.The operationof key I3 into engagement with its contact 4| provides current from negative battery 42 of suincient strength to operate station relays I 4, 22, and 25, under which conditions relay I4 operates to engage its contact I6 and thus to operate the signal device 2|, relay 25 operates to energize relays 26 and 21 to control the local circuit of receiving printer 23, and relay 22 operates inefiectively because the circuit of receiving printer 23 has been closed at relay 21. Thus, in response to key I3 in engagement with its contact 4|, signal device I9 is not operated because tongue I1 moves away from contact I6, receiving printer 23 is not operated because its circuit is controlled by relay 21, and signal device 2| is operated solely because tongue I1 is moved against contact I6. Alternatively, when the key I3 is operated to engage its contact 41, positive current is supplied by battery 48 to stations I2 of suificient strength to operate relay I4 to engage its contact I5, relay 25 is operated to energize relays 26 and 21, and relay 22 is not operated-or is operated to close its contact because of, the direction or polarity of the applied current. Thus signal device I 9 will be operated solely.

With key 6 in position as shown in the figure, operation of the transmitter I will provide in line 9 signaling currents of suflicient volume to operate relay 22 at each station and of volume be selectively connected into groups.

The invention has been described with reference to a specific system of switches and circuits designed to illustrate the principles of the invention, but its utility is not limited by the specific form shown, being limited only by the scope of the appended claims.

What is claimed is:

1. In a signaling system, a single line circuit, a station having a polar relay in series with said line circuit operable on current of a predetermined strength, a polar relay connected in series with the first mentioned polar relay operable on current of lesser strength, and means operable on the same current strength as the first mentioned polar relay for rendering the second mentioned polar relay ineffective.

2. In a signaling system, a single line circuit, a station having a plurality of signaling devices, means in said line circuit operable on current of apredetermined strength for controlling certain of said signaling devices selectively, a polar relay connected in series with said means and operable on a lesser current for controlling a signaling device, and means operable on the same current strength as the first mentioned means for disabling the signaling device controlled by the polar relay.

3. In a signaling system, a single line circuit, a station having a plurality of signaling devices, means in said line circuit operable on current of a predetermined strength for controlling certain of said signaling devices selectively, means connected in series with the first mentioned means and operable on a lesser current for controlling a signaling device, and means in series with the first and second mentioned means and operable upon the same current strength as the first mentionedmeans, for disabling the signaling device controlled by the second mentioned means.

4. In a signaling system, a line conductor extending to a station, two normally open local circuits, a polar. relay at said station responsive to currents of a predetermined value for controlling said circuits selectively, two audible signal producing devices, one in each of said circuits, a recording device at said station responsive to currents of a value lower than said predetermined value, and means at said station. operating in response to currents of said'predetermined value only to disable said recording device, said polar relay, recording device and disabling device being connected in series.

5. In a signaling system, a single line circuit, a station having a polar relay in series with said line circuit operable on current of a predetermined intensity, a polar relay connected in series With-the first mentioned polar relay operable on current of lesser intensity, a non-polar relay operable on the same current intensity as the first mentioned polar relay for controlling the effectiveness of the second mentioned polar relay, and means whereby said non-polar relay is energized simultaneously with said polar relays.

6. In a signaling system, a single line circuit, a station having a polar relay in series with said line circuit operable on current of .a predetermined intensity, a polar relay connected inseries with the first mentioned polar relay operable on current of lesser intensity, a non-polar relay in series with said line circuit operable on current of said predetermined intensity, and means controlled by said non-polar relay for rendering the second mentioned polar relay inefiective.

7. In a signaling system, a single line circuit including a polar relay operable on current of a predetermined intensity, a polar relay operable on current of lesser intensity, and a non-polar relay operable on the same current intensity as the first mentioned polar relay, armatures operable by each of said relays, a plurality of circuits selectively closable by the armature of the first mentioned relay, a signal producing device in each of said circuits, a circuit closable by the armature of the second mentioned polar relay, a signal recording device in said circuit, a cascade circuit closable by the armature of the non-polar relay, a shunt circuit across the armature of the second mentioned polar relay, and means controlled by the cascade circuit for closing the shunt circuit.

ABRAHAM S. BENJAMIN. 

